1. Field of the Invention
The invention relates to an oral smokeless tobacco product and, more particularly, a smokeless tobacco product prepared from a tobacco extract.
2. Description of Related Art
There are many oral delivery forms of tobacco. Such forms include chewing tobacco, chewing gum, lozenges, capsules, and tablets. Chewing tobacco utilizes chopped or shredded tobacco, which is placed in the mouth and ultimately removed from the mouth. Lozenges, tablets, and the like, are often designed to dissolve slowly in order to administer nicotine over a period of time. Such products are often obtained by chopping the tobacco plant or leaf and then extracting soluble components from the tobacco using a solvent. The resulting extract is dried and combined with other ingredients to form the products.
U.S. Pat. No. 3,368,567 describes a tablet having a tobacco concentrate and which is intended to be located in the mouth of the user. In preparing the tablet, nicotine and other active ingredients are extracted from cured tobacco that has been ground into fine particles. The tobacco is steeped in water and then concentrated mineral acid is added. The resulting liquid is applied to an absorbent, inert, edible base, to the extent that it constitutes less than 10% of the base. After the liquid is dried, the resultant material is compressed into a tablet.
U.S. Pat. No. 4,991,599 describes a fiberless tobacco product for smoking or chewing. The fiberless tobacco product is obtained by forming an aqueous extract of the tobacco. Cured tobacco leaves are preferably shredded or comminuted to minute particles, and boiling water or water vapor is passed through the particles to produce an aqueous, fiberless extract of tobacco. The aqueous extract is dried to product a solid extract. The solid then is crushed into smokable or chewable particles.
U.S. Pat. No. 5,387,416 describes extracting cured tobacco leaves with water to form a liquid extract. The liquid extract is concentrated to a solids concentration of about 30% dissolved solids, which is then spray dried to form a spray dried powder. The powder is then dissolved and added to gelatin, for example, and processed to form a tobacco composition that can be placed in the cheek.
Other products utilize a package containing a tobacco product that is placed in the mouth. The tobacco diffuses through the package and the package is ultimately taken out of the mouth and thrown away. Such products include SNOOSE wherein tobacco is placed in a mesh pouch and placed in the mouth. U.S. Pat. No. 4,907,605 directed to using a water-insoluble material (could be similar to a tea-bag) to dispense nicotine in the mouth.
There is a developing market for smoking cessation aids. Most notably have been the transdermal or transmucosal devices to allow delivery of nicotine through the skin or mouth. Other delivery forms include lozenges, tablets, and pills.
U.S. Pat. No. 5,512,306 describes a smoking cessation aid in the form of an inclusion complex formed between nicotine and a cyclo compound such as polysaccharide. U.S. Pat. No. 5,525,351 is directed to a saliva-soluble stimulant formed from a gel and nicotine, while U.S. Pat. No. 5,783,207 describes forming a compressed tablet containing a matrix material and nicotine whereby the compressed tablet is attached to a holder for insertion into the mouth.
U.S. Pat. Nos. 5,135,753; 5,362,496; and 5,593,684, are each directed to the combination of transdermal nicotine delivery along with transmucosal or buccal delivery of nicotine. The latter delivery may be in the form of lozenges, gum, tablets, or capsules.
However, these products suffer in that they deliver a product too high in nitrosamines, which are carcinogens believed to be formed predominantly during curing. The group of nitrosamines identified in tobacco products include tobacco-specific nitrosamines (TSNAs) such as Nxe2x80x2-nitrosonornicotine (NNN), 4(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK), Nxe2x80x2-nitrosoanatabine (NAT) and Nxe2x80x2-nitrosoanabasine (NAB). It is believed that nitrosamines may be derived from tobacco alkaloids, of which nicotine is the most prevalent. It has been postulated, according to one group of researchers, that nicotine is nitrosated to form NNN, NNK and/or 4-(N-methyl-N-nitrosamino)-4-(3-pyridyl) butanol (NNA) (Hoffman et al., xe2x80x9cFormation, Occurrence, and Carcinogenicity of N-Nitrosamines in Tobacco Productsxe2x80x9d in O""Neill et al., N-Nitroso Compounds: Occurrence, Biological Effects and Relevance To Human Cancer, World Health Organization, 1984). Hecht et al., xe2x80x9cTobacco specific N-Nitrosamines Occurrence, Carcinogenicity, and Metabolismxe2x80x9d Amer. Chem. Soc., 1979, postulated that NNN in unburned tobacco is at levels in the range of 0.3-9.0 ppm in cigarette tobacco, 3.0-45.3 ppm in cigar tobacco, 3.5-90.6 ppm in chewing tobacco, and 12.1-29.1 ppm in snuff. Up to 35 xcexcg/g of NNK has been detected in tobacco, 0.2-8.3 xcexcg/g in snuff products, and 0.1-0.5 mg/cig in cigarette smoke.
Generally, high nicotine and nitrosamine contents are found in lamina whereas stems contain lower levels of nicotine and nitrosamines. Stems typically have a nicotine content that is 50% or more lower than the nicotine content in lamina.
The invention is directed to a smokeless tobacco product made from an extract of cured tobacco. According to one aspect of the invention, a smokeless tobacco product suitable for human consumption comprises a solid tablet having at least 50 wt %, preferably at least 60 wt %, more preferably at least 75 wt %, powdered tobacco, based on the total dry weight of the tablet.
In one preferred embodiment of the invention, the powdered tobacco consists essentially of an extract of tobacco stems. Preferably, the tobacco stems consist essentially of Virginia flue tobacco.
In another preferred embodiment, the smokeless tobacco product includes eucalyptus in an amount effective to remove bitterness from the powdered tobacco.
According to a preferred aspect of the invention, the smokeless tobacco product has a very low nitrosamine content. Preferably the powdered tobacco has a collective content of Nxe2x80x2-nitrosonornicotine (NNN), 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK), Nxe2x80x2-nitrosoanatabine (NAT) and Nxe2x80x2-nitrosoanabasine (NAB) which is 0.1 xcexcg/g or less, preferably 0.05 xcexcg/g or less, more preferably 0.03 xcexcg/g or less. Preferably, the powdered tobacco has an NNK content of less than about 0.002 xcexcg/g, more preferably less than 0.001 xcexcg/g, and even more preferably less than about 0.0005 xcexcg/g. Preferably, the powdered tobacco has an NNN content of less than about 0.1 xcexcg/g, more preferably less than about 0.05 xcexcg/g, and even more preferably less than about 0.03 xcexcg/g.